The present invention relates to a collapsible keyboard.
There have been various proposals for collapsible keyboards for use with computers and particularly for use with portable computers. One of the main constraints when attempting to reduce the size of a portable computer is the fact that the keyboard must be greater than a certain minimum size in order to be usable by a person. If a keyboard is too small, the keys become too small and cramped to be used effectively. In several prior art proposals, including for example that shown in U.S. Pat. No. 3,940,758, the number pad of the keyboard is positioned on a separate part of the keyboard which is attached to the main portion of the keyboard holding the alphabetic and other control keys so that the number pad can be folded over onto the main part of the keyboard when the keyboard is not in use, thereby to reduce the overall size of the keyboard. However, in practice, this still does not reduce the overall size of the keyboard very much. As the other components of portable computers, such as display screens and hard disk drives, become increasingly smaller as the technology improves, there is an increasing need to reduce the overall size of the keyboard. Furthermore, there are various computers available now or shortly which do away with a keyboard and use a pen input to a touch-sensitive screen or voice-activation for example. However, users often find a keyboard convenient to use, but do not wish to carry a separate keyboard with them as keyboards have conventionally been very bulky. There is therefore also a need for an independent keyboard which can be used as an optional accessory to a computer and which is conveniently stored when not in use. Such a keyboard could also be used with mobile telephones, electronic organisers and potentially with interactive television systems, screen telephone units, and the like.
EP-A-0640489 discloses a foldable computer which has a keyboard which can be folded in half about a central axis transversely of the keyboard and which is attached to a separate portion containing the processor which is foldable about an axis arranged longitudinally of the keyboard.
U.S. Pat. No. 5,459,461 discloses an inflatable keyboard which can be deflated and then rolled or folded for storage and inflated for use.
According to the present invention, there is provided a collapsible keyboard, the keyboard being collapsible between a deployed configuration in which the keyboard is generally planar and a collapsed configuration, the keyboard being foldable about three substantially parallel axes between the deployed and collapsed configurations, the keyboard having four rigid subframes for supporting keys, each subframe being connected at a folding axis to an adjacent subframe.
Preferably, the keyboard is foldable in one direction about the middle axis and in the opposite direction about the adjacent axes. Thus, the keyboard may fold through a xe2x80x9cWxe2x80x9d shape so as to collapse in a concertina-like fashion.
The keyboard may have keys at least some of which are slidable in the plane of the keyboard in a direction transverse of said axes. As the keyboard is folded, the slidable keys, which in the deployed configuration may overlap a folding axis, can move away from said folding axis so as to facilitate or allow folding of the keyboard and also to provide a straight edge with no keys overlapping the folding axes in the collapsed configuration.
At least some of the slidable keys may be connected to other keys by flexible means passing over an axis so as to cause said at least some slidable keys to slide as the keyboard is folded. The keyboard is constructed such that at least some of the slidable keys are biased toward their deployed position when the keyboard is deployed.
The keyboard may further comprise a support structure for keys. The support structure is preferably a matrix of cells, each cell accommodating a respective key. In the collapsed configuration, the support structure preferably encases each depressed key. This protects and hides the key mechanism, particularly at the edges of the folding axes in the collapsed configuration. Where some of the keys are slidable, corresponding portions of the support structure may be slidable with the slidable keys.
A lock may be provided for locking the keyboard in its deployed configuration. The lock may comprise locking elements that are biased into recesses in subframes of the keyboard. The lock may be releasable by operation of a button connected to the locking means.
A lock may also be provided for locking the keyboard in its collapsed configuration.
The keyboard may be combined with a remote control unit. This has particular application for use with a television type unit, for example.
While reference is made herein primarily to the keyboard being useful for a portable computer, it will be appreciated that the principles of the present invention can be applied to a keyboard for a desktop computer, a so-called xe2x80x9cpersonal digital assistantxe2x80x9d or xe2x80x9celectronic organiserxe2x80x9d, or used as an independent portable pocket-sized keyboard for use with such devices, or, indeed, to any kind of generally planar input device such as a keyboard for a musical instrument such as an electric piano or synthesizer.